I need to determine when a DBError instance returned from listFolder: or downloadData: is because of an Invalid Access Token. So far I can see how to transform the DBError into a DBRequestAuthError using:
[error asAuthError]
provided [error isAuthError]. And I can see how to check for Invalid Access Token in an instance of DBAuthError using [... isInvalidAccessToken]. But I don't know how to get from a DBRequestAuthError to a DBAuthError. isInvalidAccessToken: does not apply to class DBRequestAuthError.